Adjustable intrusion tube for use with whistling signalling device



Aug. 21, 1956 ADJUSTABLE fNTRUSION TUBE FOR USE WITH WHISTLINGSIGNALLING DEVICE G M. SCHUTTER 2,759,489

Filed Feb. 6, 1953 Q2111 1:; .i;;; J-.u I 3 6 42 A E 6 i ii E F .6. g

132291222302 Gena-{9e MSW,

United States Patent ADJUSTABLE INTRUSION TUBE FOR USE WITH WHISTLINGSIGNALLING DEVICE George M. S'chutter, West Newton, Mass., assignor toSeully Signal Company, Cambridge, Mass., a corporation of MassachusettsApplication February 6, 1953, Serial No. 335,464

4 Claims. (Cl. 137-558) This invention relates to audible signallingdevices of the type used in connection with the filling of tanks toindicate that filling is proceeding properly and to give a, signal whenthe liquid level in the tank has risen to a predetermined desired level.

In particular, the invention relates to an improved intrusion tube whichis associated with the signalling device and which depends into thetank. A signalling device with which this invention is especially usefulis shown in the patent to Mathey, Serial No. 2,135,522, granted November8, 1938, for Liquid Level Indicator. The disclosure herein shows asignalling device of the same type as that shown in the aforesaid Matheypatent and having attached thereto an improved type of adjustableintrusion tube.

One of the objects of the present invention is to facilitate theinstallation of the signalling device in a tank. The length of theintrusion tube is determinative of the time when the whistling soundwill be cut off or altered to advise the operator that a certain liquidlevel has been reached.

It is customary to use an intrusion tube long enough to give a signal tothe operator when the tank has a remaining capacity of, say, fifteengallons. If this signal is to be given in a conventional 275 gallon tankinstalled in vertical position, the intrusion tube must necessarily belonger than the tube that would be used when the tank is installed inhorizontal position. Similarly, if the signal is to be given at otherremaining capacities, then, of course, the length of the intrusion tubewould have to be correspondingly altered.

Therefore, because of the varying lengths of intrusion tubes requiredfor diiferent installations, it has been customary for the manufacturerof these signals to furnish the signalling unit equipped with anintrusion tube long enough to function properly under the maximumconditions that will be met, While an intrusion tube of this maximumlength may be acceptable for some installations, it will not beacceptable for many others. Accordingly, it is necessary for theinstaller to consider the length of intrusion tube required at eachinstallation and cut the intrusion tube with a hack saw or otherwise tothe length required to meet the particular conditions.

In addition to the time consuming requirement of physically cutting theintrusion tube, it oftens happens that the installer incorrectlyestimates the length of the intrusion tube required with the result thathe cuts the tube too long or too short. If cut too long, the unit mustbe removed, the tube cut again to the proper length, and thenreinstalled. If cut too short, it is necessary to install anothercomplete unit, cutting the tube in the second case to the proper lengthas the too short intrusion tube of the first unit obviously can not belengthened to meet the requirements.

With these conditions in mind which have persisted for many yearswithout correction, although the need has been present, I haveconstructed an intrusion tube in which the length may be varied at willwithout in any ice 2. way afiecting, the operating characteristics ofthe device. That is to say, the sound characteristic of the whistleproduced as the. displaced gas flows through the intrusion tube andwhistle to the vent pipe will not be aifected, and similarly after therising liquid has trapped the lower end of the intrusion tube gas maycontinue to escape thereafter through the fixed by-pass in the upperpart of the intrusion tube without interference regardless of theadjusted length of the tube. In other WOrdS,, the intrusion tube of thepresent invention while adjustable in length will function the same asthe heretofore supplied one piece intrusion tube specifically cut to thelength required.

A further object of the invention is the provision of a whistle unitthat will be of constant weight regardless, of they length of theintrusion tube. A constant weight unit will provide better Whistlingcharacteristics as the relief pressure. remains constant.

These and other objects of the invention will become more apparent asthe description proceeds with the aid of the accompanying drawings, inwhich:

Fig. 1 shows the signalling unit inserted in normal position in a tankwith the adjustable intrusion tube extended its full length.

Fig. 2 is the same as Fig, 1 except that the intrusion tube has beenshortened somewhat.

Fig. 3 is the same as Figs. 1 and 2 except that the intrusion tube hasbeen reduced to minimum length.

Fig. 4 is a section on the line 44 of Fig. 1.

Fig. 5 is a section on the line 5-5 of Fig. 2.

Fig. 6 is a view of the intrusion tube looking from the right of Fig. 2.

The casing and whistle shown herein is old and no claim in made to thispart of the disclosure. The invention resides in the construction of theintrusion tube and its relationship to the other parts of the signallingdevice, and of which further explanation will now be made.

As shown in the drawings, the signalling unit consists of a casing 2threaded at its upper end internally at 4 for connection with aconventional vent pipe. The casing is threaded at its lower end at, 6 bymeans of which it is placed in engagement with the threads 8 in the topof the tank 10.

The casing has a circular seat 12 on which rests a ball shaped valve 14usually made of type metal and which has set therein a button typewhistle 16. Stops 18 and 20 act to limit the upward movement of valve 14so that the valve cannot block the lower end of the vent pipe (notshown) which is screwed to the upper end of casing 2.

The valve and whistle have depending therefrom an intrusion tube 22which is in series with and axially aligned with the ports 24 and 26 ofthe whistle. The intrusion tube consists of two parts, an upper tubularportion 28 and. a. lower adjustable tubular portion 30. In the upperportion a short distance below the lower end of the casing is a fixedpermanently open by-pass 32 which, regardless of the position of thelower adjustable. portion, is always open for the passage of gas afterthe lower end of the. intrusiontube has been trapped by rising liquid.In the several figures the liquid level is indicated at 34 at a pointwhere it had risen just above the lower end of the intrusion tube.

The construction of the upper and lower portions 28 and 30 of theinstrusion tube is as follows: Near the bottom of portion 28 a smallarea 36 has been punched outwardly to act as a stop to the downwardmovement of the lower portion 30. The lower portion comprises a tubeordinarily made of sheet metal with its vertical edges overlapped as at38 and maintaining close frictional and slidable engagement with theexterior of upper portion 28.

This tube has a vertical tunnel 40 extending most of its length and thespace in the tunnel is denoted at 41. The tunnel is of such dimensionsthat the stop 36 fits closely within, permitting portion 30 to be movedup and down but preventing any rotation with respect to portion 28. Theupper end of tunnel 40 terminates in an inwardly turned finger 4-2having on either side V-shaped notches 44 and 46. The bases of thesenotches as shown in Fig. 4 are spaced as at 48 and 50 from the exteriorof portion 28 and provide free and open passages from the exterior ofthe tube to the tunnel interior 41. The finger 42 acts as means forlimiting the descent of portion 39 with respect to portion 28 byengagement with stop 36 as shown in Fig. 1. Stop 36 may also act asmeans for limiting upward movement of portion 30 by engagement with thebottom end of tunnel lit as shown in Fig. 3. However, due to the lengthof portion 28, it will be noted that the upward movement of portion 30is also limited by its engagement with the under side of valve 14.

The openings provided by the bulged areas 48 and 59 permit the free flowof air into the interior 41 of tunnel 4t? regardless of the verticalposition of portion 30. Thus, gas will always be able to flow throughby-pass 32 after the trapping of the lower end of the tube, directlywhen the upper end of portion 38 is below the by-pass and via tunnel 41when the upper end of portion 30 is above bypass 32.

The fixed open by-pass 32 is an important feature because it isessential that there always be a port to permit continued venting of gasafter the bottom end of the intrusion tube has been trapped. When thebottom end has been trapped by the rising liquid, the whistle ceases tosound, giving an indication to the operator that the liquid level hasrisen to the desired point. However, if the inflow of liquid to the tankis not immediately out ofi, then the level will continue to rise but thegas in the top of the tank instead of being compressed until valve 14lifts from seat 12 will be permitted to continue its escape to the ventpipe through by-pass 32. By-pass 32 whose location in portion 28 iscritical is so positioned that gas passing therethrough after theintrusion tube has been trapped will be sutficiently distorted on itsway to the Whistle openings 24 and 26 so that little or no sound will beproduced. Thus, venting will continue after the trapping of the lowerend of the intrusion tube, so long as the by-pass 32 is not interferedwith.

The weight of the Whistle unit obviously will remain constant regardlessof the length of the intrusion tube. This constitutes a distinctadvantage over the prior constructions in which the weight varied withthe length of the one piece intrusion tube. Constant weight of the unitcauses the valve 14 to open at constant tank pressure and gives uniformwhistling characteristics regardless of tube length.

In order to facilitate the movement of portion 30 with respect toportion 28, finger gripping elements 52 are provided at the lower end ofportion 30. Elements 52 may be readily formed by a suitable die used onthe metal of portion 30 before it is formed into its tubular shape.

It is my intention to cover all changes and modifications of the exampleof the invention herein chosen for purposes of the disclosure which donot constitute departures from the spirit and scope of the invention.

I claim:

1. An adjustable instrusion tube for use with a liquid level indicatingdevice of the type described, said tube comprising two tubulartelescoped portions open at both ends and slidable one within the other,the upper of said portions having an opening through the wall thereofand a stop extending outwardly below said opening, the lower of saidportions including a longitudinal tunnel in which said stop ispositioned to limit downward movement of said lower portion with respectto said upper portion and to guide said tunnel to a position over saidopening when the upper end of said lower portion has been moved upwardlyto a position above said opening, and a passage to the exterior of saidlower portion at the upper end of said tunnel whereby when said lowerportion has been moved with respect to said upper portion so that saidtunnel covers said opening, gas may flow into said tunnel and thencethrough said opening.

2. An article of manufacture for use With an audible signalling deviceof the type described, comprising a whistle, a valve supporting saidWhistle and a variable length intrusion tube in series with saidwhistle, said intru sion tube comprising a pair of telescoped tubularelements open at both ends, the upper of said elements having its upperend fixed in relation to said whistle and having an opening through thewall thereof and the lower of said elements being slidablelongitudinally with respect to said fixed element and in substantiallysealed engagement therewith, said lower element having means forpermitting gas to flow to said opening when the upper end of said lowerelement has been moved to a position above said opening.

3. An. adjustable intrusion tube for use with a liquid level indicatingdevice of the type described, said tube comprising two tubulartelescoped portions open at both ends and slidable one within the other,said portions being in substantially sealed engagement with each other,the upper of said portions having an opening through the wall thereof,and the lower of said portions including an interior passage throughwhich gas may flow from the exterior of said lower portion through saidopening when the opening is covered by said lower portion.

4. An adjustable intrusion tube for use with a liquid level indicatingdevice of the type described, said tube comprising two tubulartelescoped portions open at both ends and slidable one within the other,said portions being in substantially sealed engagement with each other,the upper of said portions having an opening through the wall theerofand the lower of said portions having a raised longitudinal tunnel withan opening from said tunnel communicating with the exterior of saidlower portion and means for maintaining said tunnel positioned over saidopening of said upper portion whenever said portions are telescoped tothe extent that the lower of said portions has covered said opening.

References Cited in the tile of this patent UNITED STATES PATENTS915,867 Lee Mar. 23, 1909 2,135,522 Mathey Nov. 8, 1938 2,239,921Majewski Apr. 29, 1941 2,468,667 Holbrook Apr. 26, 1949 2,531,950 ScullyNov. 28, 1950 2,638,222 Roach May 12, 1953

